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s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR

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Make the call chain more reliable by tagging the ftrace stack entries
with the stack pointer that is associated with the return address.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2019-02-18 16:51:28 +01:00
parent 78c98f9074
commit ec7bf4789d
5 changed files with 11 additions and 8 deletions
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2
arch/s390/include/asm/ftrace.h
View File

@ -11,6 +11,8 @@
#define MCOUNT_RETURN_FIXUP 18
#endif
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
#ifndef __ASSEMBLY__
#ifdef CONFIG_CC_IS_CLANG

2
arch/s390/kernel/entry.h
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@ -65,7 +65,7 @@ int setup_profiling_timer(unsigned int multiplier);
void __init time_init(void);
int pfn_is_nosave(unsigned long);
void s390_early_resume(void);
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip);
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip);
struct s390_mmap_arg_struct;
struct fadvise64_64_args;

9
arch/s390/kernel/ftrace.c
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@ -201,17 +201,18 @@ device_initcall(ftrace_plt_init);
* Hook the return address and push it in the stack of return addresses
* in current thread info.
*/
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
unsigned long prepare_ftrace_return(unsigned long ra, unsigned long sp,
unsigned long ip)
{
if (unlikely(ftrace_graph_is_dead()))
goto out;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
goto out;
ip -= MCOUNT_INSN_SIZE;
if (!function_graph_enter(parent, ip, 0, NULL))
parent = (unsigned long) return_to_handler;
if (!function_graph_enter(ra, ip, 0, (void *) sp))
ra = (unsigned long) return_to_handler;
out:
return parent;
return ra;
}
NOKPROBE_SYMBOL(prepare_ftrace_return);

4
arch/s390/kernel/mcount.S
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@ -65,8 +65,8 @@ ENTRY(ftrace_caller)
.globl ftrace_graph_caller
ftrace_graph_caller:
j ftrace_graph_caller_end
lg %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
lg %r3,(STACK_PTREGS_PSW+8)(%r15)
lmg %r2,%r3,(STACK_PTREGS_GPRS+14*8)(%r15)
lg %r4,(STACK_PTREGS_PSW+8)(%r15)
brasl %r14,prepare_ftrace_return
stg %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
ftrace_graph_caller_end:

2
arch/s390/kernel/unwind_bc.c
View File

@ -84,7 +84,7 @@ bool unwind_next_frame(struct unwind_state *state)
/* Decode any ftrace redirection */
if (ip == (unsigned long) return_to_handler)
ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
ip, NULL);
ip, (void *) sp);
#endif
/* Update unwind state */